One of my three black-eyed susans (Rudbeckia fulgida "Little Suzy") is turning brown and dying. The problem seems to be progressing from one side of the plant to the other, with the leaves and stalks turning brown and drying up. Some of the stalks and flowers seem to be wilting before they turn brown, though. I've posted a photo (4 MB) at

http://www.jpmccaskey84.net/tcbenner/Show/brown_bes.jpg

There seems to be plenty of air flow on that side of the plant - roughly the northeast side - and the surrounding plants seem OK. However, I lost all four beardtongues (Penstemon digitalis "Husker Red") on that side late last summer, as well as a fourth black-eyed susan, and as I recall they similarly turned brown and died.

After I took the photo, I cut away all the dead bits. I also gave it some water, as we've had several sprinkles lately but no sustained rain for a while, and the soil was dry down to a couple inches.

Any opinions and advice would be much appreciated.

There are many diseases that affect Rudbeckia. Looking at the image, it looks a lot like Verticillium wilt. This disease affects the water-conducting tissues of the plant. Often, the plant wilts on one side and then turns brown. It can mimic drought even though there is ample moisture. Control of this disease involves removal of the dead portions, which you indicate you did. Drainage is critical as poorly drained soils can exacerbate the disease. I don't see any other foliar diseases on the picture so can rule out leaf spots, mildew. If you choose to replant in that location, you might consider removing that soil, if possible. Any soil added should be loosened up with organic matter.